• Journal of KIISE:Information Networking
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• v.31 no.2
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• pp.196-206
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• 2004

In the Next Generation Internet(NGI) backbone network, a Dense Wavelength Division Multiplexing (DWDM) technology has been more and more highlighted to cover the increasing subscribers and bandwidth requirement. For such a DWDM network, Routine and Wavelength Assignment (RWA) is the essential problem to establish the optimal path and assign a wavelength efficiently to the selected path in resource utilization. However, the existing RWA algorithms do not consider the congestion in the network so that the performance of then is so limited. To solve this problem, in this paper, we introduce a new RWA algorithm, called Multi Wavelength-Minimum Interference path Routing (MW-MIPR) that establishes a routing path to minimize the interference for many potential future connection setup request. And then, we also propose a wavelength-routed QoS routing scheme based on differentiated QoS classes with applying MW-MIPR algorithm. Simulation results are also given to prove the efficiency of the proposed algorithms.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.12
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• pp.1138-1147
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• 2012

IEEE standard 802.16, often referred to as WiMAX, is considered a "last mile" broadband wireless access alternative to conventional DSL and Cable Internet. One extension that is recently receiving great attention is the IEEE 802.16j Mobile Multihop Relay (MMR) amendment. The focus of this amendment is the development of simple and lower cost relay stations (RSs) that can enhance network coverage and capacity. We use our proposed simple scheduling scheme for serving the SSs in a fair manner and evaluate the performance of WiMAX networks with relays, especially we analyze the impact of interference between RSs on cell throughput Through simulations and numerical analysis, we make several fundamental observations about interference aware cost effective coverage extension in such networks.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.4
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• pp.389-400
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• 2008

As the wireless network technologies and the capability of the mobile terminals are evolving, advanced peer to peer applications for mobile users are attracting interests. In this paper, we propose the mobile P2P communication platform(MPCP) which provides transparency to the wireless network technologies and solutions to the limited resources of the mobile terminals. MPCP classifies the connection into two levels: a virtual channel and a session. A virtual channel is the network layer connection between the terminals whereas a session is the application layer connection. MPCP classifies the sessions into four types and applies different scheduling priority and data processing policies such as segmentation and reassembly. It selects proper wireless network technologies depending on the distance between the communication endpoints. To acquire dynamically changed access address, we harness the Session Initiation Protocol. We implemented MPCP on embedded Linux simulator and utilized the implementation in mobile P2P service development. For the quantitative analysis, we compared the performance of MPCP with that of ftp. Regardless of the number of simultaneous sessions, MPCP maintains the relative performance.

• Journal of the Institute of Convergence Signal Processing
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• v.19 no.3
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• pp.133-138
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• 2018

VR technology is a technology that allows a user to experience virtual reality close to reality by wearing an HMD (Head Mounted Display) device. Recently, as the interest in VR technology increases due to the 4th industrial revolution, various HMD devices are spreading. As a result, VR technology is being rapidly applied to various fields, but many of them still experience VR nausea. VR nausea is caused mainly by visual factors, unlike motion nausea, such as car nausea, sea nausea, and air nausea. Such occurrence of VR nausea may be caused by the characteristics of visual information of VR video contents, the hardware characteristics of HMD devices blocking the external visual field, or the physical specificity of individuals, and it is difficult to distinguish the causes. In this paper, we aim to analyze the characteristics of Visually Induced Motion Nausea images focusing on VR video content, which is the cause of VR nausea, in order to search for minimization of Cyber sickness occurrence.

• Science of Emotion and Sensibility
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• v.9 no.4
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• pp.321-329
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• 2006

Recently there has been interested in the role of emotion in human computer interaction fields. The present study investigated whether the users emotional state effects on information search pattern for decision making in small screen display. In experiment, to induce specific emotional states(positive and negative emotional state), the participants were asked to listen to music and imagine autobiographic events with different emotional impacts. Subsequently, they performed time limit search tasks with three travel information on small screen display and their search patterns were recorded on real time. The results indicated that a positive emotional state caused more wide and fast Information search pattern in comparison with neutral and negative emotional state. And neutral and negative emotional state caused more cognitive resource to details in comparison with positive emotional state.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.11C
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• pp.1081-1089
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• 2002

In these days many Organizations recognize risk of information asset by rapid change of information system environments, and need suitable management for that. Also many organization which operate important information-communication infrastructure take interest in threat, vulnerability and risk analysis of important asset by enforcement of Act on protection of information and communication infrastructure. But, it is most that methodology and tools that analyze risk for organization's information asset are developed in abroad up to now, domestic research of this field is insufficient stage. An research of this field is necessary in domestic because it can't reflect domestic actuality by depending on most foreign methodology or a tool. In this paper we proposed design and implementation for the risk analysis methodology, a prototype and important modules that considers the user convenience. We expect that the result of this paper will for step improvement of domestic risk analysis methodology and tool development.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.10B
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• pp.883-890
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• 2006

The study of sensor network database is beginning to liven up as we are interested in Ubiquitous Computing technology in hardware, communication, database and so on. Especially, as new smart sensors have capabilities of real-time information gathering and analysis of each sensor node, data processing becomes an important issue in Ubiquitous Computing. In thesis, we have applied TinyDB(query processing system) to carry sensor node with line tracer which can follow the fixed path. After we gathered data around path, we have processed data in TinyDB GUI, gathered data, displayed data on a web server. Also we have a web browser on an embedded board for convenient user interface and implemented touch screen such that users can operate with a finger.

• Journal of the Korea Society of Computer and Information
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• v.12 no.2 s.46
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• pp.209-220
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• 2007

Mobile devices become a pak of our daily life due to their versatility, such as the wireless phone calls, the wireless accessibility to Internet, the display of multimedia content, and the communication with nearby mobile devices. Third generation telecommunication service provides an easy access to the Internet for nubile devices. Mobile users pay a fee charged by the telecommunication provider based on the amount of data transferred. This paper introduces a special ad hoc network in which mobile devices cooperate each other to download an interesting content from the Internet in order to reduce the telecommunication cost. The mobile devices, called the peers, in the ad hoc network are assigned a portion of the target file, and are responsible for downloading the portion using their 3G connection. Then, the peers exchange their downloaded portion with other participating peers using their cost-free ad hoc connection in order to reconstruct the whole content. According to the simulation results, large number of participating peers saves the telecommunication cost up to 90% with as few as 10 peers, although it slightly increase the overall content reconstruction time.

• Journal of Broadcast Engineering
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• v.7 no.1
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• pp.2-9
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• 2002

Recently. VR( Virtual Reality) applications such as virtual studio and virtual character are wifely used In TV programs. and AR( Augmented Reality) applications are also belong taken an interest increasingly. This paper introduces a virtual screen system. which Is a new AR application for broadcasting. The virtual screen system is a real-time video augmentation system by tracking a chroma-patterned moving panel. We haute recently developed a virtual screen system.'K-vision'. Our system enables the user to hold and morse a simple panel on which live video, pictures of 3D graphics images can appear. All the Images seen on the panel change In the correct perspective, according to movements of the camera and the user holding the panel, in real-time. For the purpose of tracking janet. we use some computer vision techniques such as blob analysis and feature tracking. K-vision can work well with any type of camera. requiring no special add-ons. And no need for sensor attachments to the panel. no calibration procedures required. We are using K-vision in some TV programs such as election. documentary and entertainment.

• Journal of Internet Computing and Services
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• v.10 no.5
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• pp.1-12
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• 2009

A routing policy based on BGP community routing permits to select a specific route for particular network by making use of user-defined routing policies. Especially, community based routing policy is recently getting a great concern to enhance overall performance in the global research networks which are generally inter-connected large number of different characterized networks. In this paper, we analyze the community routing which has been applied in existing global research networks in the network performance point of view, and catch hold of problems caused by the routing performance in a new global research network. Then, we suggest an effective community routing policy model along with an interconnection architecture of research networks, in order to make correct some wrong routings and resolve an asymmetric routing problem, for a new global research network. Our work is expected to be utilized as an enabling base technology to improve the network performance of future global research networks as well as commercial networks.